『Abstract
Australia's Large Igneous Provinces (LIPs) span almost the entire
Earth's geological history, ranging from Early Archean to Recent.
LIPs in continental Australia are represented by continental flood
basalts, fragments of oceanic plateaux, volcanic rifted margins,
layered mafic-ultramafic intrusions, sill complexes, dyke swarms
and silicic-dominated volcanic provinces. In the last decade or
so, several geologists have started to focus on LIPs in Australia,
mainly from the perspective of their mineral potential, particularly
after the discovery of the Nebo-Babel Ni-Cu-PGE deposit in the
West Musgrave Province, central Australia. Wingate et al. (2004a)
further advanced the inventory of LIPs with the announcement of
a new LIP (ca. 1070 Ma Warakurna, extending for nearly 1500 km
along an E-W trend), based on U-Pb dating of baddeleyite from
mafic sills and dykes. The list of LIPs increased by including
other well-known igneous provinces, such as the Fortescue, Hart-Carson,
Kalkarindji (formerly known as Antrim Plateau Volcanics) and various
dyke swarms (e.g., Widgiemooltha, Marnda Moorn, Gairdner). The
Bunbury Basalt, although only covering a small area in the Cape
Naturaliste-Cape Leeuwin Peninsula, joined the list of LIPs, due
to its age links with the huge Kerguelen Plateau in the Indian
Ocean. As indicated by the world-class Nebo-Babel deposit (>1
Mt contained metal) and further discoveries in the West Musgrave
and in the Kimberley region, the LIPs in these regions have good
mineral potential. In the case of orthomagmatic mineral systems,
the selection of areas or specific intrusions requires focusing
on trace- and major-element geochemical trends to filter out mafic-ultramafic
intrusions that may not have undergone sulphur saturation from
those that have experienced sulphur saturation from processes,
such as crustal contamination. In addition, consideration must
be given to hydrothermal mineral systems that may have been generated
as a result of thermal energy inputs, related to the emplacement
into the crust of mafic-ultramafic magmas, as exemplified by recent
discoveries in the West Musgrave Province. In eastern Australia,
the Early Cretaceous Whitsunday volcanic province, is the largest
known silicic LIP and comparable to the Chon Aike silicic LIP
in South America. The mineral potential associated with the Whitsunday
province is as yet not fully assessed. Similarly, the mineral
potential for the Bunbury, Tasman Dolerite and Kalkarindji volcano-plutonic
provinces is poorly known and yet to be fully explored. We conclude
our contribution by providing a short review of crustal and mantle
dynamics associated with LIP emplacement.
Keywords: Large Igneous Provinces (LIPs); Australia; Layered intrusions;
Dyke swarms; Silicic LIPs; Mineral systems; Mantle plumes』
Contents
1. Introduction
2. Australia's LIPs
2.1. Preamble
2.2. Archaean flood volcanism: the Fortescue Group LIP, Pilbara
Craton
2.2.1. The 2.7 Ga Fortescue flood volcanism; age and stratigraphy
2.2.1.1. The Fortescue continental flood basalts (CFB), the
end result of a long-lived mantle Archaean superplume, or a series
of mantle plume event?
2.3. Proterozoic dyke swarms in Australia
2.3.1. Widgiemooltha dykes; 2.4 Ga
2.3.1.1. Dyke orientations
2.3.1.2. Ages
2.3.1.3. Lithologies
2.3.2. Marnda Moorn dyke swarm; 1.2 Ga
2.3.3. Gairdner Dyke Swarm; 827 Ma
2.4. 1.8-1.7 Ga Hart-Carson LIP, Kimberley region
2.4.1. Carson Volcanics
2.4.2. Hart Dolerite
2.5. 1.6 Ga Gawler Range Volcanics and Hiltaba suite
2.6. West Bangemall sill complex; 1.4 Ga
2.7. Warakurna LIP; 1.07 Ga
2.7.1. Sill complexes and mafic dykes of the Warakurna LIP
2.7.1.1. Weld Spring Member
2.7.2. The Warakurna LIP in the Musgrave Province
2.7.2.1. Mafic dykes
2.7.3. Discussion
2.8. Kalkarindji LIP; 510 Ma
2.9. Tasmanian dolerites
2.10. Bunbury Basalt; 130-110 Ma
2.11. The Whitsunday silicic volcanic province; 120-105 Ma
3. Mineral systems associated with LIPs
3.1. Introduction
3.2. Mafic-ultramafic-related Ni-Cu-PGE
3.2.1. Mafic related Fe-Ti-V oxides
3.3. Magmatic-hydrothermal
3.4. Giant hydrothermal systems linked to emplacement if LIPs
4. Mineral systems associated with Australia's LIPs
4.1. Mineralisation in the ca 2.4 Ga Jimberlana Dyke (Eidgiemooltha
dyke swarm)
4.2. Mineralisation in the ca 1.8 Ga Hart-Carson LIP
4.3. Mineralisation associated with the Gawler Range Volcanics
and Hiltaba Suite
4.3.1. Olympic Dam
4.4. Mineralisation in the Musgrave Province
4.4.1. Mineralisation in Giles mafic-ultramafic rocks
4.4.1.1. Wingellina nickeliferous ochres and chrysoprase
4.4.1.2. Nebo-Babel No-Cu-(PGE) deposit
4.4.1.3. Vanadiferous titano-magnetite
4.4.1.4. Prospectivity analysis and discussion
4.5. Mineral potential of Tasman Dolerite
4.6. Giant hydrothermal circulation possibly linked to LIPs in
Australia
4.6.1. Mineral systems associated with the Whitsunday SLIP
5. LIPs and mantle dynamics in the Australian context: discussion
and conclusions
5.1. Overview
5.2. Crustal doming, rifting, triple junctions, basin-forming
events and LIPs
5.3. Australian LIPs
Acknowledgements
Appendix A. Supplementary data
References